Consumer electronic equipment has been further advanced in the recent trend toward high-speed and low power consumption for microcomputers etc., and semiconductor elements for semiconductor devices used in such computers are also miniaturized rapidly. Accordingly, undesirable radiation, that is, electromagnetic wave noise generated from electronic equipment, has been a serious problem. As a method to decrease such undesirable radiation, a technique to integrate capacitor elements with a large capacity in semiconductor integrated circuit devices and the like has attracted attention. Such capacitor elements have capacitor dielectric layers of dielectric with high dielectric constant (hereinafter, high dielectric). With the trend toward high integration of dynamic RAM, a technique to use high dielectric materials for a capacitor dielectric layer instead of conventional silicon oxides or nitrides is widely researched. Moreover, research and development concerning ferroelectric films having a spontaneous polarization characteristics have been attracted much attention in order to practically apply a non-volatile RAM that enables writing and reading with lower operating voltage and higher speed compared to conventional devices.
A method for manufacturing a conventional semiconductor device is explained below referring to FIGS. 6A to 6C. FIGS. 6A-6C are cross-sectional views showing the process of manufacturing conventional capacitor elements.
As shown in FIG. 6A, a film 12 for an electrode or a capacitor dielectric layer is formed on a substrate 11 composed of a semiconductor or the like by sputtering or a metal organic decomposition method, followed by forming a mask 13 for patterning the film 12. Next, as shown in FIG. 6B, the film 12 for the electrode or the capacitor dielectric layer is patterned by dry-etching. Subsequently, as shown in FIG. 6C, the mask 13 is removed.
In the semiconductor device manufactured in the conventional method, however, as shown in FIG. 6B, the dry-etching is accompanied by generating a reaction product 14 that adheres to sides of the mask 13. As the product 14 remains after removing the mask 13, a thin film formed to cover the capacitor element may suffer from inferior coverage, which prevents the capacitor element from operating normally.